Focal nodular hyperplasia and hepatocellular adenoma: current views

Focal Nodular Hyperplasia (FNH) is a rare benign hepatic lesion believed to generate upon a hyperplastic response of the hepatocyte. Hepatocellular Adenoma (HA) occurs predominantly in young women receiving oral contraceptive medication. These two lesions have drawn significant attention throughout the recent years due to their specific clinical and pathological features as well as their challenging management. Although Focal Nodular Hyperplasia is managed conservatively in the majority of cases, it can albeit pose a difficult diagnostic dilemma. On the other hand, Hepatocellular Adenoma can be complicated with catastrophic hemorrhage or malignant transformation and therefore mandates surgical excision in many cases. The aim of this work is to review the current literature pertaining to these two clinical entities regarding their pathogenesis, diagnostic approach and genetics, as well as to shed light on specific differential diagnostic issues arising in many cases these lesions are encountered.